Calcium (Ca2+) plays an important role in the transduction of signals into and within cells. Many cell types depend on the generation of calcium signals to regulate numerous cell functions or to trigger specific responses. For example, cytosolic calcium signals control cellular functions such as short-term responses (e.g. contraction and secretion) and long term regulation of cell growth and proliferation. These signals generally involve some combination of release of calcium from intracellular stores, such as the endoplasmic reticulum (ER), and influx of calcium across the plasma membrane. For example, cell activation may begin with a ligand binding to a surface membrane receptor, coupled to phospholipase C (PLC) and/or a G-protein regulated mechanism. PLC activation leads to the production of inositol 1,4,5-triphosphate (IP3), which may activate the IP3 receptor causing release of calcium from the ER. The decrease in ER calcium may signal the plasma membrane store-operated calcium (SOC) channels.
Store-operated calcium (SOC) influx is a process that controls many diverse functions including e.g., refilling of intracellular calcium stores, activation of enzymatic activity, gene transcription, cell proliferation, and release of cytokines. In certain nonexcitable cells (e.g., blood cells, immune cells, hematopoietic cells, T lymphocytes and mast cells), SOC influx occurs through calcium release-activated calcium (CRAC) channels, a type of SOC channel.
Since calcium plays an important role in cell function, differentiation and survival, dysregulation of calcium in cells can have adverse effects on cell structure and function. Numerous diseases (e.g., immune disorders, inflammatory disorders, and allergic disorders) are linked with calcium dysregulation. Accordingly, new compounds and methods for modulating calcium in cells are needed to treat or prevent these diseases. The present application addresses these needs.